Exceptions to GNU Licenses

Autoconf Configure Script Exception

The purpose of this exception is to allow distribution of
Autoconf's typical output under terms of the recipient's choice
(including proprietary). This is necessary because Autoconf includes
some of its own code—which would otherwise be licensed under
GPLv3—in its output.

GCC Runtime Library Exception

The purpose of this exception is to allow developers to compile
non-GPLed software with GCC, as long as they don't use proprietary
plugins or other extensions to the compiler. An additional permission
is needed for this because GCC normally includes some GPLed code in
the binaries it creates.

URLs

When linking to the exceptions of GNU licenses, it's usually best
to link to the latest version; hence the standard URLs such as
http://www.gnu.org/licenses/gcc-exception.html have no version number.
Occasionally, however, you may want to link to a specific version of a
given license exception. In those situations, you can use the
following links: